In order to increase the range of speed ratio in a toroidal continuously variable transmission for vehicles, U.S. Pat. No. 5,935,039 and Tokkai Sho 63-219956 published by the Japanese Patent Office in 1988 disclose an infinite speed ratio transmission device using a toroidal continuously variable transmission (CVT) with double cavity, fixed speed ratio transmission and planetary gear set. In such an infinite speed ratio transmission device, an engine output is input to the CVT and fixed speed ratio transmission. The output shaft of the CVT is joined to a sun gear of the planetary gear set, and the output shaft of the fixed speed ratio transmission is joined to a planet carrier of the planetary gear set via a power circulation mode clutch. A ring gear of the planetary gear set is joined to a final output shaft of the transmission device which drives the wheels. The output shaft of the CVT is also joined to the final output shaft via a direct mode clutch.
In this device, two types of power transmission are used, i.e. a direct drive mode wherein the direct mode clutch is engaged and the power circulation mode clutch is disengaged, and a power circulation mode wherein the direct mode clutch is disengaged and the power circulation mode clutch is engaged. In the direct drive mode, the engine output is transmitted to the drive shaft via the CVT. In the power circulation mode, the rotation of the ring gear stops at a position where the rotation of the sun gear due to the output of the fixed speed ratio transmission and the rotation of the planet carrier due to the output of the CVT are balanced. This state corresponds to a neutral state where rotation torque is not transmitted to the drive shaft. In this case, the ratio of the engine speed and the rotation speed of the final output shaft becomes infinite.
With respect to the construction of the CVT, Tokkai Hei 9-317837 published by the Japanese Patent Office in 1997 discloses an upper link and lower link for displacing trunnions facing each other with opposite phase in the axial direction. The upper link is supported by a post fixed to a casing via a pin.